Method for starting up a heating device, control device, heating device and computer program

Abstract

A method for starting up a heating appliance (1) is proposed. The appliance is designed to burn a mixture of combustion air and fuel gas, which is supplied to a burner (3) by means of a conveying device (2). The method comprises at least the following steps: a) starting up the conveying device (2) and accelerating to a starting speed (21), b) recording a speed profile (18, 20) of the conveying device (2) during the execution of step a), c) comparing the speed profile (18, 20) recorded in step b) with a reference profile (19), evaluating the speed profile (18, 20) recorded in step b), and detecting a blocked condensate drain (12). The method enables the detection of a blocked condensate drain (12) during the start-up process of a heating appliance (1).In addition, a computer program, a control and regulating device (7), a heating device (1) and the use of a recorded speed profile (18, 20) are proposed.

Description

[0001] The invention relates to a method for commissioning a heater, a control and regulating device, a heater and a computer program.

[0002] A large number of heating devices are known which burn a mixture of a fuel, in particular natural gas or hydrogen, and ambient air in a combustion chamber in order to generate heat to supply a building or to provide hot water.

[0003] When such heaters are started up, a delivery system is typically started up to a predetermined or specific starting power or speed, and fuel is added to the volume flow of drawn-in combustion air thus delivered. The resulting combustion mixture is fed to a burner located in a combustion chamber of the heater and ignited by an ignition device, such as a spark or glow igniter.

[0004] Condensate produced during a combustion process (e.g. of natural gas or hydrogen) is, according to the state of the art, led from the combustion chamber and the heater to a drain via a condensate drain, often comprising a siphon. A blocked drain or siphon can lead to significant problems, even when starting up a heater. If the drain is blocked, the condensate can rise in the combustion chamber and possibly flow into the burner or even further into the gas supply. This can cause significant damage to the heater and require costly repair. There are ways to detect a blocked condensate drain. However, these require the heater to be started up, which could cause damage if the condensate drain is already blocked.

[0005] For example, the detection of a blocked condensate drain using ionization current-based flame detection is known, with the ionization electrode being arranged below the burner. In a blocked condensate drain, the condensate could only collect up to the level of the ionization electrode because, upon contact between the ionization electrode and the condensate, the ionization current breaks off and the heater switches off due to a lack of flame detection. Such a solution is described, for example, in EP 3 081 861 A1. However, this solution cannot be used with hydrogen-powered heaters because a hydrogen flame does not release sufficient electrical charge carriers to detect an ionization current, and thus a collapse of the ionization current due to a ground fault of the ionization electrode caused by a rise in condensate level cannot be detected.The process cannot be used before the ignition of a heater in order to avoid critical start-up processes.

[0006] DE 10 2015 206 810 A1 describes such a method in which, during normal operation of a burner device, a PWM control signal of a fan of the burner device and an ionization current of an ionization probe are detected in order to detect a blockage of a siphon of the burner device. The disadvantage is that the burner device must be put into operation for this purpose, and, as explained above, the method cannot be used with hydrogen-powered burners.

[0007] In addition, mechanical means of preventing condensate buildup in a heater must be avoided. For example, GB 2187 829A proposes collecting condensate generated in the heater in a container to prevent a heater drain from becoming blocked and then emptying the entire container via the drain. GB 249 7140 A proposes installing a connector with a switch in a condensate drain pipe that can be activated by the condensate flowing out of the drain pipe. The switch can then trigger another switch to shut off the heater via communication means.

[0008] EP 3 754 258 A1 describes a method for fault detection in a fluid supply device, in particular a combustion plant. In this method, an operating parameter of a fluid delivery unit is recorded, and in a further method step, a change parameter of the operating parameter is recorded.

[0009] These solutions are complex and / or require structural modifications to a heater, which not only increases the likelihood of failure but also increases manufacturing and assembly costs. Furthermore, their use in hydrogen-powered heaters is not readily possible or sufficiently safe.

[0010] Based on this, the object of the invention is to propose a method for starting up a heating device that at least partially overcomes the problems described in the prior art. In particular, a particularly simple and universally applicable method is to be proposed.

[0011] In addition, the invention should at least not significantly increase the complexity of a heater, require only minor structural changes to a heater and enable easy integration into an existing production process.

[0012] These objects are achieved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It is pointed out that the features listed in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features specified in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0013] A method for commissioning a heating device contributes to this, which is configured to burn a combustion mixture of combustion air and fuel gas. The combustion mixture can be fed to a burner by means of a conveyor device (which can be controlled via a speed control), which is arranged in a combustion chamber having a condensate drain.

[0014] The procedure includes at least the following steps: a) Commissioning the conveyor system and starting it at a (specified) target speed; b) Recording a (temporal) speed curve of the conveyor system (at least partially) during the execution of step a); c) Comparing the speed curve recorded in step b) with a reference curve, evaluating the speed curve recorded in step b), and detecting a blocked condensate drain.

[0015] Steps a), b), and c) can be performed at least once in the specified sequence during regular procedure execution. As stated, steps a) and b) can be performed in parallel or simultaneously. In particular, steps a) to c) can be performed during or as part of each commissioning of the heater. The comparison, evaluation, and determination processes in step c) can be performed in this order, if necessary, even repeated several times within this step c).

[0016] The procedure serves to ensure a safe ignition process or safe commissioning of a heater and can in particular help to detect a blocked condensate drain of a heater before fuel gas is supplied during a start-up process.

[0017] The heating device can comprise at least one heat generator, in particular a gas condensing boiler, which releases heat energy through the combustion of a fuel and can transfer it to a heating circuit via at least one heat exchanger. A circulation pump in the heating circuit can be configured to circulate a heat transfer medium (heating water), whereby the heated heat transfer medium can be supplied to consumers, such as convectors or surface heating systems, via a heating flow and returned to the heat generator or the at least one heat exchanger via the heating return. Exhaust gases generated during combustion can be discharged to the outside via an exhaust duct of the heating device and a downstream exhaust system.

[0018] The heater can have a conveying device, in particular a fan, which can supply a mixture of combustion air and fuel (hydrogen) to a burner of the heater. The conveying device can comprise a power control, in particular a speed controller. The heater can form a pneumatic gas-air system in which a mass flow of combustion air, corresponding to a negative pressure (control pressure) of a throttle point, such as a Venturi nozzle, is added to a mass flow of fuel gas provided via a gas supply, so that a predefined (specified) combustion air ratio (air ratio, lambda) can be established. Alternatively, the heater can have an electronic gas-air system in which, based on a signal from a flame monitor, a conclusion can be drawn about the flames and the combustion air ratio (also referred to as lambda or air ratio), thus enabling control of the same.The heater can be designed, in particular, to burn hydrogen as a fuel or a mixture containing hydrogen. The mixture can have a hydrogen content of at least 80% or at least 90%.

[0019] Condensate (liquid or watery) produced during fuel combustion in the combustion chamber can drain from the heater's combustion chamber via a condensate drain. The condensate drain can include a siphon that prevents gas exchange between the combustion chamber and the surrounding area. A siphon can be a mostly U-shaped condensate drain pipe that can fill with condensate during operation and thus prevent gas exchange, in particular the ingress of external air into the combustion chamber, through the condensate drain. The condensate can be directed to a suitable location, such as a sewer, via the condensate drain and / or the siphon.

[0020] The condensate drain can be located at the (geodetically) lowest point of the combustion chamber (in the operating position) to ensure the most complete drainage of the condensate. A blockage of the condensate drain can be caused, in particular, by or within the siphon. A blockage of the condensate drain can result in its complete closure or in such a reduced drainage velocity that the condensate cannot drain sufficiently quickly and collects in the combustion chamber. A "blockage" is therefore understood here, in particular, to mean that the condensate cannot drain away or can only drain away insufficiently, and consequently collects or backs up (partially or to a significant extent) in the combustion chamber.

[0021] The heater can also have flame monitoring. An ionization electrode is often used for this purpose, which can use the ionization current of the flame to detect it. However, this principle cannot be robustly applied to a hydrogen flame, as significantly fewer free charge carriers are produced during the combustion of hydrogen. Therefore, other methods are often used in hydrogen-powered heaters, such as detecting the electromagnetic radiation emitted by the flame, particularly infrared (IR) and / or UV (ultraviolet) radiation, or detecting the flame temperature. A signal from a flame monitor can indicate the presence of a flame and also allow conclusions to be drawn about the combustion air ratio of the flame.

[0022] The heater may also have an ignition device arranged on the burner in such a way that the combustion mixture emerging from the burner can be ignited. The ignition device may, in particular, be an electrical ignition device whose power is electrically controllable.

[0023] Commissioning a heater can proceed as follows: First, a control unit of the heater, for example, can start or accelerate a conveying device, which is preferably designed as a fan, to a predetermined starting power or starting speed. Subsequently, once the starting power or starting speed has been reached, a safety valve on the gas supply can be opened, thus releasing the gas. A mass flow of fuel predetermined for the starting speed can then be added to the mass flow of combustion air conveyed by the conveying device. An ignition process by commissioning the ignition device can form a flame and start the heater.A method proposed here is intended to enable the detection of a blocked condensate drain during a start-up process before gas is released and thus to help avoid critical conditions caused by a start-up process with a blocked condensate drain.

[0024] According to step a), the conveyor system can be started up and started up to a (predetermined, e.g., stored) starting speed. For this purpose, a starting speed can be specified for a speed controller of the conveyor system, for example, by the control unit of the heater.

[0025] According to step b), a speed profile of the conveyor system can be recorded (measured) during the execution of step a). For this purpose, a speed signal can be recorded and stored, for example, in a memory of the control unit.

[0026] According to step c), the speed curve recorded in step b) can now be compared with a reference curve, the speed curve recorded in step b) can be evaluated and a blocked condensate drain can be detected.

[0027] A reference curve for the speed of the conveying device can, for example, be determined in advance as part of (laboratory) tests on a reference heater and represent a speed curve on the reference heater with a (by definition) blocked and / or free condensate drain. By comparing the speed curve recorded in step a) with the reference curve, significant differences can now be identified and (as a result of the comparison) it can be determined whether a blocked condensate drain is present. Because the cross-sections of the flow paths of the heater change when the condensate drain is blocked and are available for gas flow, a blocked condensate drain can be reliably detected and identified based on the speed curve when the speed jumps to the starting speed during commissioning of the heater.

[0028] According to one embodiment, if the heater detects a blocked condensate drain, it can abort the start-up process and refuse to release gas, i.e., it cannot open the gas valve, in particular the gas safety valve. This can prevent a critical start-up process due to a blocked condensate drain.

[0029] According to one embodiment, if a blocked condensate drain is detected, the heater can be put into an error state, which prevents re-startup or can only be performed by a qualified person. A critical ignition process can be detected, for example, by exceeding a pressure limit in the heater's gas supply or by a lack of or insufficient flame formation.

[0030] According to a further embodiment, information about the detection of a blocked condensate drain or about the heater entering a fault state can be displayed via a display device (external or integrated into the heater) and / or made available for retrieval via a network, in particular the Internet, and / or sent as a message. For example, the information can be made available for retrieval on an appliance interface of the heater or on a network storage device (cloud). Advantageously, for example, a user / operator of the heater and / or a specialist company can be informed of the detection of a blocked condensate drain via a message, and the specialist company can plan and carry out an appointment for maintenance and / or repair accordingly. In particular, this can bring about a rapid resolution of a fault state in the heater.

[0031] According to a further aspect, a computer program is also proposed, which is configured to (at least partially) carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising commands which, when executed by a computer or, in particular, a control and regulation unit of the heater, cause the computer to carry out a method proposed here. The computer program can, in particular, be executed on or by a control and regulation unit of the heater.

[0032] According to a further aspect, a machine-readable storage medium on which the computer program is stored is also proposed. The machine-readable storage medium is usually a computer-readable data carrier.

[0033] According to a further aspect, a control and regulating device for a heater is also proposed, configured to carry out a method proposed here. For this purpose, the control and regulating device can, for example, have and / or be equipped with a processor. In this context, the processor can, for example, execute the method stored in a memory (of the control and regulating device). For this purpose, the control and regulating device can, in particular, be electrically connected to a conveying device and a gas valve of the heater. In addition, data acquired or required within the scope of carrying out a method proposed here can be stored in a memory of the control and regulating device, for example a speed curve acquired in step b) and / or one or more reference speed curves for carrying out step c).

[0034] According to a further aspect, a heating device is also proposed, configured for burning a combustion mixture of combustion air and fuel gas, which can be fed to a burner by means of a conveying device, and comprising means adapted to carry out the steps of the method proposed here. The means may comprise a regulating and control device. The heating device may be a gas heating device, in particular a hydrogen-powered gas heating device. The gas heating device may have a burner and a conveying device with which a mixture of fuel (hydrogen) and combustion air can be fed to the burner.

[0035] A recorded speed curve of a heater's conveyor system can be used to detect a blocked condensate drain of the heater. In particular, a reference curve can also be used, which can be compared with the recorded speed curve to detect a blocked condensate drain.

[0036] The details, features, and advantageous embodiments discussed in connection with the method can also be applied to the computer program, the control unit, and the heater presented here, and vice versa. In this respect, reference is made in full to the explanations therein for a more detailed characterization of the features.

[0037] Thus, a method for commissioning a heater, a control device, a heater, and a computer program are provided here, which at least partially solve the problems described with reference to the prior art. In particular, the method for commissioning a heater, the control device, the heater, and the computer program, as well as their use, at least contribute to preventing critical conditions during commissioning of a heater due to a blocked condensate drain.

[0038] In addition, the invention can be implemented particularly advantageously without structural changes to a heating device in the form of a software implementation.

[0039] As a precaution, it should be noted that the numerals used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and therefore do not necessarily specify any interdependence and / or sequence of these objects, quantities, or processes. Should a dependence and / or sequence be required, this is explicitly stated here or will be obvious to the person skilled in the art upon studying the specifically described embodiment. To the extent that a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or part of the majority of these components, but this is not mandatory.

[0040] The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures, and in particular the proportions shown, are only schematic. They show: Fig. 1 : a heater proposed here, Fig. 2 : a sequence of a procedure proposed here, and Fig. 3 : Parameter curves that can occur when carrying out a procedure proposed here.

[0041] Fig. 1 shows, by way of example and schematically, a heating device 1 proposed here. This can comprise a burner 3 arranged in a combustion chamber 8. Combustion air can be sucked in via a combustion air supply 4 by a conveying device 2, in particular designed as a fan. The conveying device 2 can be connected to a speed controller 6, which can regulate a speed n of the conveying device 2 by means of a pulse width modulated (PWM) signal. A gas valve 5 can add fuel gas from a gas supply 14 to the sucked-in air mass flow of combustion air and can comprise a safety valve and a gas control valve for controlling the mass flow of fuel gas to be added. The produced mixture of fuel gas and combustion air can flow via a mixture channel 11 to the burner 3 and be ignited there by the ignition device.The burner 3 can have a cylindrical shape, which can be attached by a base surface to a burner door 15 such that combustion mixture can flow from the mixture channel into the burner 3. After combustion, the combustion products can be discharged to the outside via an exhaust pipe 9 of the heater and an exhaust system 10. Condensate produced during combustion in the combustion chamber 8 can collect in a lower region of the combustion chamber and be discharged from the combustion chamber 8 via a condensate drain 12 of the heater 1 and fed to a drain. The condensate drain 12 can comprise a siphon 17.

[0042] The heater 1 can also have a flame monitor 13 on or in the burner door 15, which can be configured as a sensor for UV (ultraviolet) radiation emitted by the flame. The flame monitor 13 can indicate the presence of a flame or be used to control the combustion process.

[0043] A control and regulation device 7 can be configured to regulate the heating device 1. For this purpose, it can be electrically connected, for example, to the speed controller 6, the conveyor device 2, the gas valve 5, the flame monitor 13, and a network 16 (Internet). The control and regulation device 7 can be configured to implement a method proposed here.

[0044] Fig. 2 shows, by way of example and schematically, a sequence of a method proposed here. The execution of steps a), b), and c) represented by blocks 110, 120, and 130 can be performed at least once in the specified order during a regular method sequence. The method serves to increase the safety of a heater 1, in particular one operated with hydrogen or a hydrogen-containing mixture as fuel, during commissioning or an ignition process. The method enables the detection of a blocked condensate drain 12 of the heater 1 during a start-up process prior to gas release, i.e., opening of a gas valve 5.

[0045] Fig. 3shows, by way of example and schematically, a first speed curve 18, a reference curve and a second speed curve 20 of the speed n of the conveying device 2 of the heater 1 as a function of time t (given in seconds) when the conveying device 2 starts up to a starting speed 21, which in the present case can be in a range of approximately 5400 rpm [revolutions per minute]. The first speed curve 18 was recorded with a free condensate drain 12 and the second speed curve 20 with a blocked condensate drain 12. The reference curve 19 represents an expected speed curve with a free condensate drain 12. In the range of approximately 0.1 s [seconds], a speed jump to approximately 3000 rpm [revolutions per minute] can be seen in the second speed curve 20, which indicates a blocked condensate drain 12.

[0046] In block 110, according to step a), the conveyor device 2 can be started up and started up to a starting speed 21. Step a) can be initiated and carried out by the control unit 7 of the heater 1.

[0047] In block 120, according to step b), a speed curve 18, 20 of the conveyor device 2 can be recorded during the execution of step a). Step b) can also be performed by the control unit 7 of the heater 1, wherein the recorded speed curve 18, 20 can be stored, in particular, in a memory of the control unit.

[0048] In block 130, according to step c), the speed curve 18, 20 recorded in step b) can be compared with a reference curve 19, and the speed curve recorded in step b) can be evaluated based on the comparison, and a blocked condensate drain 12 can be determined. In the present case, a blocked condensate drain 12 can be detected in the second speed curve 20 based on the speed jump at approximately 0.1 s to approximately 3000 rpm. This speed jump cannot be detected in the reference curve 19 and thus represents a feature for determining a blocked condensate drain 12. List of reference symbols

[0049] 1Heater 2Feeding device 3Burner 4Combustion air supply 5Gas valve 6Speed ​​controller 7Control unit 8Combustion chamber 9Exhaust pipe 10Exhaust system 11Mixing duct 12Condensate drain 13Flame monitoring 14Gas supply 15Burner door 16Network 17Siphon 18First speed curve 19Reference curve 20Second speed curve 21Starting speed

Claims

1. Method for starting up a heating appliance (1) designed to burn a combustion mixture of combustion air and fuel gas, which is supplied to a burner (3) by means of a delivery device (2), comprising at least the following steps: a) Commissioning of the conveying device (2) and starting up to a starting speed (21); b) Detecting a speed curve (18, 20) of the conveying device (2) during the execution of step a); c) Comparing the speed curve (18, 20) detected in step b) with a reference curve (19), evaluating the speed curve (18, 20) detected in step b) on the basis of the comparison and determining a blocked condensate drain (12).

2. Method according to claim 1, wherein, when a blocked condensate drain (12) is detected in step c), a start process is interrupted and the gas supply (14) is not enabled.

3. Method according to one of the preceding claims, wherein the heating appliance (1) is taken out of operation and placed in a fault state when a blocked condensate drain (12) is detected in step c).

4. Method according to one of the preceding claims, wherein information about a detected blocked condensate drain (12) in step c) and / or about the heating appliance (1) being placed in a fault state is displayed via a display device, made available for retrieval via a network (16) and / or sent by means of a message.

5. Control and regulating device (7) for a heating appliance (1), designed to carry out a method according to one of claims 1 to 2 F 4, wherein the control and regulating device is designed to carry out the following steps: a) Starting up a conveying device (2) of the heating appliance (1) and starting up a starting speed (21); b) Detecting a speed curve (18, 20) of the conveyor device (2) during the execution of step a); c) comparing the speed curve (18, 20) detected in step b) with a reference curve (19), evaluating the speed curve (18, 20) detected in step b) on the basis of the comparison and detecting a blocked condensate drain (12).

6. Heating appliance (1) designed to burn a combustion mixture of combustion air and fuel gas, which can be supplied to a burner (3) by means of a conveying device (2) and has a regulating and control device (7) according to claim 5.

7. Computer program comprising commands which cause the heating appliance (1) of claim 6 to carry out the method steps according to one of claims 1 to 4.

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